Check manual page of mqtt_clients

MQTT: Clients

Distribution Official part of Checkmk
License GPLv2
Supported Agents Mqtt
This check monitors client related statistics of a MQTT broker instance.

It shows the number of currently connected clients", the maximum number of clients connected at the same time and the total number of active and inactive clients currently connected and registered on the broker.

To make this check work you have to configure the special agent agent_mqtt which connects via MQTT to the broker to gather information from the $SYS/ topic.

This check has been developed with Mosquitto message broker but might also work with other brokers. The available values vary from broker to broker and from version to version.

Please note that this check may only be useful if you connect it directly to a broker. In case you want to monitor a multi-tentant cluster, this check is only useful if configure it for each node since the $SYS/ topic is is node specific. It is not useful to use this check through a load balancer.

The check is always OK.


The instance ID configured in the special agent.


One service is created for each instance.